Circuit controlling device



Oct 14, 1947- A. P. CHARBONNEAU 2,428,832

C IRGUIT C-ONTROLLING DEVICE Filed June 7, 194; s sheets-sheet 3 i 54 'Y 59 54 I vJI-6.50 87a 50 Patented Oct. 14, 1947 CIRCUIT CONTROLLING DEVICE" Allan P; Charbonneau, Wauwatosa, Wis., assignerto Cutler-Hammer, Inc., Milwaukee,l Wis., a

corporation of Delaware Application June 7, 1943, Serial rN0...489,887

10I Claims. l;

This invention relates to circuit controlling devices, and more particularly to limit switches of the snap-action type.

The invention has among its objects to provide an improved snapaction; limit switch which is exceedingly simple, compact andY rugged in con'- struction, positive and reliable in operation, and which is adapted to a-variety of uses, as for eX- ample in connection'wth controllers for cranes, hoists and machine tools of various types.

Another object is to provide an improved snap action limit switch which isl constructed largely of sheet metal stampings and molded insulating parts capable of being readily manufactured and assembled at low cost.

Another object is to.. provide an improved limit switch havingnormally-open and normally closed contacts which are .readilyadjustable to provide for closureof thenormally'open contacts either before or after opening of the normally, closed contacts.

Another object is toprovide an enclosed limit switch unitwhich Without change in its construction maybe equipped. with operating heads of different types forv` lever orV push rod operation thereof.

Another object is to provide a limit 'switch having an improved lever operating mechanism which is readilyadjustable to Vrender the switch adaptable for use in a wide variety oilcontrol applications.'

Variousl other objects and advantages-of the invention will hereinafter appear.

The accompanying drawings Villustrate certain embodiments ofthe invention which will now be described; it beingV understood that various vmodi-- iications may be made in the embodiments illustrated without departing from the spirit and scope ofthe appended claims.

In the drawings;

Figure l is a perspective View of--a lever operated limitsWitch embodying `the invention;

Fig. 2 is a.. longitudinal sectional vie-w. of the limit switch shown in Fig. 1; v

Figs. 3y 4 Aand aresectional views on lines 3 3, 4,-5 and 5-5,\respectively of Fig..2;

Fig. 6 is a side elevational view of the movable contact assembly of the switch shown in Fig. 2;

Fig. 7 .is a plan view of the limit switch shown in Fig. 2,' with the cover plate removedy and the operating headshown in section;

Figs. 8 and 9. are sectional views onlines-8.-l and 9a-9, respectively.. of Figs..2 and 7;

Figi.. luis a sectionalview outline; [Ii-loof Fig.. 5;

Fig;A 11 is-a fragmentary sectional view on line FigsxlZ and 13 are-sectionalviews,` and Fig. 14.Y

isa side elevationalviewpf. different types of operating vheads-for` the switchshown7 in Fig. 2, and

Fig 15 is a sectional-viewon line I5.-I5.of` Fig. 14.

Referringto theK drawings; the. same illustrate a snap action limit 4switch comprising. amovable contact assembly Landa stationarycontact assembly. 2,- both of. .which are. mounted -within .an elongated rectangular. casing .3-havinga removable top, coverplate 4.. As hereinafter set forth, different typesy ofcperating. heads are-provided foreffecting. operation. of the switch, said operating heads being. interchangeable and being` adapted. for mounting. 1 in .various angular positions upon the front end of casing 3,

More fspeciiicallyf .the.movable contact assemblyI includes a stationaryframe 'lwhich carries a contactelementV` 6,1. a reciprocable` operating member f. 1 and. ar snapoperating mechanism inl cluding a coil spring 8. and .alatch member I9. Frame!) comprises ra. pairofelongated 'rectangular side plates4 ID-IDOfIikefOrm which are secured. together in .spacedrelation by pins I I-II fixed within openings ,adjacentopposite ends of said plates andalso ,bya pin I2 located midway between said. former pins andxed within openings in. projections I3`I3,formed. on the underside of said plates. As shown in Fig. 3, the side plates I--I'areprovided' with outwardly extending right angletop projections Id-Id for securement -to `lugs I 5+-I 5 formed on the Vinterior of casing 3.".

Contact carrying element Gis carried by a pair of verticallydisposed invertedY-shaped levers I6 and'I Twhich are arranged in .parallel relation, and are yrotatably supported. intermediate their ends upon the pins `I I associated with. frame I. Each of the levers lvand I'I comprisesa pair of stamped sheet metaLarms.. I8 .of-like forml which are are rangedin opposedrelatiom as shown in Fig. 3.

Contact carrying, element 6' is arranged above' frame. 5.=and .is pivotally. supported at opposite endsupon the-upper ends. of levers land I1.- Said contact carrying element comprises two molded'insulating sections IBL-i9 of like form arranged in `opposed relation on opposite sides of the levers IFB and. I'I. Insulating sections I9 'are formed to intert .asshown in'Fig, 8, each being provided with a pivot projection ZI) which extends through an openingyin the `upper end of one ofthe levers` I fiori-I 'I into a recess-formed in the other...insulatingfsection insulating sections I9 `vented by latch member 9.

are also formed to provide an elongated slot 2l for receiving a pair of horizontally disposed bridging contacts 22 and 23. Said bridging contacts are yieldingly supported intermediate their ends and held in assembled position within slot v2i! by a pair of insulating keepers 24 which are slidably supported within said slotand are biased apart by a spring 25. Y

l VOperating member 'i comprises a U-shaped sheet metal stamping having elongated rectangular side arms 26-26 which are slidably supportedV between the side plates IIJ- l of frame 5 and" are provided with elongated horizontally disposed slots 2 for receiving the pins Il associated with said frame. The side arms 25 of operating member 'i are also provided with horizontally disposed slots 28 and 29 which are located below theslots as shown in Fig. 2 pin 28a is located to the left cf lever I6, and pin 29a is located to the right of lever il. The Varms I8 of levers I6 and H Vare provided with V-shaped notches for receiving the pins 28a and 29a and said pins are connected by a tensoned Vcoil spring 8 which is located between the arms f I 8 of. said levers..

Latch member 9 comprises an elongated rectangular plate whichV is supported intermediate its ends by the projections YI3 on frame 5. As shown in Fig. 4, latch member 9 is notched on opposite sides to receive projections i3 and as shown in Fig. 2 the same is biased upwardly by a bow Spring 39 which bears against the underside of said latch member and is supported intermediate its ends upon the pin l2 associated with frame 5. VThe left hand Vend of latch member 9 cooperates with stop projections I62L formed on i the lower ends of the arms I8 oflever IS and the `right hand of said latch member cooperate-s with stop projections lle, formed on the lower ends of th'e arms I8 of lever |71.' ated by opposed inclined cam surfaces 3l and 32 formed on the underside of each of the side arms 26 of operating member 1 and as shown in Figs. 2 and 4 said latch member hasfinclined projections 33 formedon opposite ends thereof to be engaged by said camsurfaces.'

. The operation of the aforedescribed movableV contact assemblyk will now bemore fully described. As hereinafter set forth operating member 1 is normally held in the position shown in 1 Fig. 2 and with the same in this position the left hand end of latchy member 9 is held by the spring 30 in engagement with the stop projections I6a on lever l5. Lever I9 is thus locked against counterclockwise rotation upon its associated pin H Vto prevent movement of contact element 5 toward the left out of the extreme position shown in Fig., 2. Upon initial movement of operating member 1 toward the right out of the position i shown Vin Fig.Y 2 pin 29a Yis Yengaged by the left hand end of slot 29 and is moved to the right with respect to lever I1. Spring 8 is thus tensionednand tendsA to rotate'lever I6 in a counterclockwiseV direction, suchwmovementbeing premovement ,ofV operating member 'I toward the right into the position shown in Fig. 6 the cam surfaces 3l thereof engage the inclined projections ,33 on the left hand end of latch member 9 to move said latch member out of engagement with stop Vprojections 46a on lever 16. SpringV 8 then. acts to rotate lever VI6 in a counterclockwise Y direction for snap movement of contact carrying element r(i from'the extreme'pdsition shown in- Pins 28a and 29a are supported at opposite. ends within the slots 28 and 29, respectively, andV Latch member 9Y is actu-A Upon continued tion shown in. Fig. 2 pin 28a is engaged by the Vright hand end of slot 28 and is moved towardV is provided withslot openings 4,8Vfor receiving the Y screws 41 andthe underside Vof said base ispro- 1 vided with recesses 49 for receiving the heads of said screws. The slot openings 48 permit adjustl ment `of the pairs of stationary contacts 36 and- Fig. 2 into the extreme position shown in Fig. 6. Upon movement of contact carrying element 6 into the extreme position shown in Fig. 6 the stop projections il@ on lever l1 are engaged by the right hand end of latch member 9. Lever Il is thus locked against clockwise rotation to mantain contact carying element 6 in the extreme position shown in Fig. 6. Y

Upon initial movement of'operating member l from the position shown in Fig. 6 toward the posithe left with respect to lever I6. Spring 8 is thus tensioned and tends to rotate lever I1 in a clockwise direction, such movement being prevented by latch member 9.Y Upon continued movement lof o erating member 1 toward the left the cam surfaces 32 thereof engage the inclined projections 33 on the right hand end of latch member 9 to move said latch member out of engagement with the stop projections YI 1e onlever I1. Spring 3 then acts to 'rotate lever I1 in a clockwise direction for snap movement of contact carrying element 6 Afrom the extreme position-shown in Fig. 5 into the extreme position shown in Fig. 2.

Upon return of contact carrying element 6 into` the extreme position shown in Fig. 2 the left hand end of latch member S'reengages the stop projections 16a on lever I6 to lock said element in such position. Y

The stationary contact assembly' 2 comprises a fiat moldedinsulating base 35 of rectangular' shape having a pair of stationary contacts 364-36 Y 22 and 23, and as shown in Fig. 8 said recess isV formed to provide guide surfaces 39 which engage j said contact-carrying element on opposite sides to hold the insulating sections jl9 thereof Yin as- Y sembled position upon the upper end'of levers 46 and-H. .'Insulating base 35 andthe projections I4 on Vframe 5 are provided with aligned-openings for receiving screws 4u which thread into the lugs i5 to hold the movable contact assembly l and' i stationary contact assembly 2 in assembled position within casing 3.

frame and insulating base 35, said sheet being slotted to receive the upper ends of levers |5` and Il.

Stationary contacts 3,6 and Y3! are ofV like form',i

each comprisingy a,V sheet metal stamping which is VL-shaped to provideY a terminal portion'42 and a contact portion 43.' rIhe upper-face of insulating base Y35 is provided with recesses 44 for receiving the terminal portionsJ 42 of said stationary contacts and the contact portions 43 of said stationary contacts extendV downwardly through openings 45 in said base into the path ofnb'ridging contacts V22 andr .23. The terminalV portion 42 of.

each stationary contact is provided with a binding screw'49 and is secured torbase 35 by a screw 47. Asshown in Figs. 8 and 11 insulatinglbase 35 As shown'in Fig. 2, a sheetV of insulating material 4| is interposed between 31 for Variation of the' distance therebetween; With contacts 35and 31T spaced as shown in Fig.l 8j bridgingcontact 23-` disen'gages 'its cooperating stationary contacts 35 prior to movement of bridging contact 22 into engagement withrv its cooperating stationary contacts y31. However; if l desired, the pairs Iof-stationary'contacts 36 and 31'may be adjusted to decrease the distance therebetween so that bridging contact 22 engages its cooperating stationary con-tacts 31 priorv to movement of bridgingy contact 231 out ofA en; gagement with itsv cooperating stationary con taCS 36;

As hereinbefore stated, different types of op'- erating heads are provided for controlling the1 switch, said operating heads being interchange# able and-being adapted for mounting in anyone of several angular positions upon the front endy of casing 3. Figs- 2,' 5 and '1 of the drawings illustrate an operating head of thelever type including a reciprocable push rod 59, a rotatable cam shaft for operating said rod and a supporting block 52 forsaid parts which is rectangular in shape and is secured'to the front end of casing 3 by screws 53.

Push rod 59- is slidably supportedwithin an opening in the front wallof 'casing 3- andV hasan enlarged circular head 54 formed on the front endthereof which is guided and supported withinS abore 55 in supporting block 52.- The rear end of push rod 5||fvis provided with agroove 551land the'side arms 26'of switchoperating member 1 areprovided with inwardly bent portions 51 (Fig. 7) which engage withinsaid 'groove to operativelyv connectv said switch operating member to saidl push rod'. Push rod 50 is biased to move forwardly' by a coil spring E53-which is held under compression betweenhead 544 and the -front wall of casing 3.

Cam shaft 5| is disposed at right angles to push rod 59 and is rotatably supported within a bored opening'in block 52; Asy shownv in Fig.l 5,1 cam shaft 5|v has an operating lever 59adjustably secured to the left hand end thereof 'andthe right hand end of saidcam shaft hasa springl` same in uthe'angular position shown inF'ig.A 2L' Spring 5|)l is of coil form and is held in assembled position within an opening Yin the right hand'endv of cam shaft 5| by a washer 6|. Washer Bil fisse-f cured to cam shaft 5| by a screw {S2-and has a circular projection 63'formed on'the inner face thereof which extends through theopening in spring 69; As shown in Fig. l0, spring Eil is pro'- vided with straight radialextremities 64"and 65' and cam shaft 5| andblock 52 are recessed as shown at'55 and'51 to receive the extremities of said spring. Spring 5|) is tensionedA soI that'the extremities M'and 55thereof are biased to move apart and said spring extremities cooperate with faces 65a and 55h of recess 55, and-with faces E1*av and 51b of recess 51 to bias camshaft 5| and its associatedoperating lever 59 against rotation inopposite directions out of theintermediate po: sition shown in Fig. 2.

Rotation of cam shaft 5| in opposite directions out of the position shown in Fig. 2 is limited by a stamped sheet metal washer 68. Washer 'is rotatably supported upon projection 53of washerK 6| and is provided with a radial tongue 59 which extends into the recesses 56 land 61.u As is appar# ent from Fig. 10, clockwise rotation of cam shaft 5| is limited by engagement of tongue (iS-with' faces'a and 'lb'of recesses fand v|51, and vcoun-l tercl'oclrwise-v rotation7 thereof Ais limited =by ene- S gagementf-of said itongu'e with therfacesfan efofl'saidirecesses; Y

Cam sh'afti5l is' recessed asfsh'own: inFigii 211:0- provide-falcam portion 10 for:engagingth'erfrontv 12?,Y the formerf surface-1 being? radially disposedwith '.respect'ito-I theY axis l of cam. shaft? 5| for 'normal. 'engagement fwith the upperrhalf of 'push rodi head '54."- When :operatingdever-59 is operated a--clockwisehdirectionl out fof thev normal position shown .in .,Fig; 22'the1upper'edge `1 I@ ofsurface 1 I engages-f: therface1 of-pushf rod? head 54* to move pu's'hlrod 5lllinwardlylforfoperation: ofthe-switchV` mechanismf from'the normalposition shown'in FiggnZinto'fthefzposition"shownl'in Fig.' 6; Upon releasezzofoperating 'lever 59 'thesame is returned` to normalpositi-on"under thev actionv4 of springi andfpushlrod' 502`is moved forwardly by spring- 58 tozreturn the switch' mechanism to the normal`- positionishownlin Fig. 2. The surface 12 of 'cam-44 portion 101 permits ycounterclclckwise by-pass iro'- tationzofflever 59 and cam shaft 5| out offthe normal position shown inLFig; 2fwith'oui'ff move mentor thefswitchl-mech'anism outv offnormal'" position.

As-shownrin Fig.- 5, 1ever159'is provided/with `a-` hub 13'which is rboredf'to receivea portion 1'4'of reduceddiameter on cam'shaft'5l and t0 also receive a lock--washer-15lwhich'is xedto'a-pin extension 16 on the left'hand end'of said-shaft;l Asrfshown in Fig; 9,'lock washer 15has-ninesemicircular notches 111i formed on the* periphery4v thereof which "are spaced" 40" degrees apart andA therportion `of-hub 13 which overlapssaid washer' hasten zequallyspaced semi-circular notches 18'# formedon the interior thereof which are spaced'` 36 degrees apart. Lever 59 is heldinl assembled position -upon-fcam shaft by a washer 1Q-which is secured# to said shaft' byla screwA 80: Washer' 19 hasapin 8| xed'tothe inner face thereof andas' shown in Fig, 9'saidpin isadapted'to engagea-within a circular space formed by, a' selected notch 11 in vwasherf15, and a selected notch 18-in hub 1'3`to1ock-1ever"59against rotation with' respectfto said shaft; With'nine equallyspaced' notches-=11"in lockl washer `15f-and tenV equallS7 slsxaced'no-tches'4v on the interiorof hub 13 provi'- sionis madefor-lockinglever 59 to'canfrsh'aftfi by means of f pin 8|in any one'of ninetyyangular positions which are spaced 4 degrees apart.v As' shown'in Fig;V 5; lever"59-is offset to'clear casing. 3 andf has 'a roller 82 @mounted 'upon the free endv thereof.

As 4hereinbeforestated, supporting fblock 52"'is' secured-to casing 3 by screws 53 and' as shownin" Fig.' 57`said 1 screws extend through corner 'openings infsaid block which are equally spaced with respect to each other Vand with respect to the' axisfof-'pushrod/55;'` Block 52 maythusbe se'- curedtto casing 3f-'inl any one of four equally spaced-'angular positions for'locationof the operating-"1ever 59"eitherabove"or-v below casing, 3i or on` eitherrside thereof.

The-operating -head shownin'Fig; 12) isY similar to theloperatin'g headfshown'inligsg 2 and 5'ex= cept thatth'e-1 cam shaftis -modied' toV providea y camportion':which is 'Vesh'aped to' provide"sur"' faces 18lifand 185; Surface SIMS radially disposed? with respect Yto theaxis of "shaft 5| for'norrnal' engagement-With thef loweri'half of push 'rod "head 54. Upon countercloclwise"rotation of lever59" outof norrnalposition the edge 84a of surfaceV 84 engages the-'front face Vof head 54 to move push rod 59"inward-ly'-for'operation'offthe switch out` 7.' o'f normal position. YThe surface 85 ,permitsclockwise by-pass rotation of lever,59 outofnormal intermediate position`without movement of the switch mechanismV out of normal position.

The operating head shown in Fig.V 13 is also similar to the operating head shown in Figs. 2v and 5 except that the cam shaft is provided with a cam portion 86 having a diametrically disposed face 81 which normally engages the front face of push rod head 5d. The edges 8l2L and 81h of surface'l respectively engage push rod headV 54 upon clockwise and counterclockwise rotation of lever A59 out of normal position to effect operation of the switch mechanism out` of normal position.

Figs. 14 and 15 illustrate an operating head of the push type which may also be used in connection with the switch. The operating head shown in these figures is provided with a supporting block Quand a push rod 9|. Block 99 is cylindrical in form and has a square flange 92 formed on the rear end thereof Vfor securement to casing 3 by screws which areY located as shown in Fig. 5. Push rod 9! is similar to push rod 50 exceptV that the front end thereof is provided with an enlarged cylindrical head 93 having a iiangel projection 93a formed on the rear end thereof to be engaged by the spring 58. Block 90 is bored to receive head 93 and is recessed Vas shown at 94` to receive flange 93a and to also provide shoulder $5 for engaging said ange to limit forward movement of the push rod under the action of spring 5B. Head 93 and block 9B are'slotted to receive a roller 96 which is secured to said head by a pin 91. Push rod 9| is normally held in the position shown in Figs. 14 and 15 by spring 58 and isi movable inwardly from such position by means of roller 96 to move the switch mechanism out of normal position. Y

As shown in Fig. 7, casing 3 is provided with corner'mounting holes 98 which are llocated outside of the switch compartment. -As shown in Figs. 2 and 7, casing 3 extends rearwardly beyond the switch mechanism to provide a wiring space f 99 and the rear wall of said casing is provided with aV threaded conduit receiving lug mi). In-

Vsulating sheet lil extends downwardly over ythe other of said levers upon inovementof said conl tact elementinto its other extreme circuit controlling position, an operating member movable in oppositeV directions between given extremey positions and acting during movement into one extreme position to trip saidlatch out of engagement with one of said levers and during-move- Vrnent into its other extreme position to trip said latch out ofrengagementwith the other of said levers, and a spring operating connection between saidroperating member and said levers for effect-- ing snap movement of said` contact element'be-l tween its "extreme circuit controlling positions upon tripping of'said latch.

Y 2. In a circuitrcontrolling device, in combinaltion,V a horizontally disposed contact element movable inroppo'site directions between given extreme circuit controlling positions, a pair of vertically disposed pivoted leversV supporting said element and movable in parallel relation to operate the same, a latch extending between said levers and acting to lock one of-said levers'upon movement of said contact element into one extreme circuitcontrolling position Yand to lock the other of said levers upon movement of said contact element into its opposite Vextreme circuit controlling position, a horizontally disposed operating member movable in opposite directions between given extreme positions andacting during movement into one extreme position to trip said latch out of engagement with one of said levers Y and during movement into its opposite extreme I position to trip said latch out of' engagement with'the other of said levers, and a single spring operating connection between` saidl operating member and said levers for effecting snap movement of said contact element between its extreme circuit controlling positions upon trippingV of said latch, Y Y Y 3. In a control switch,-in combination, a stationary frame, a pair of vertically disposed parallel levers each pivotally supported intermediate its endsupon said frame, acontactcarying elementflocatednabove said frame and pivotally conv nected at opposite ends to the upper ends of said levers for movement by saidlevers in opposite directions between given circuit controlling posi- Y tions, a latch member carried by said frame-and operating to lock one of said levers upon move'- 'ment of said contact element intoone extreme circuit controlling position and to lock the other of said levers upon movement of said contact element into its' other rextreme circuit controlling position, an operating member movable in opposite directions between given extreme positions and having cam surfaces thereon acting during movement into one extreme position to trip said latch outl of engagement with one of said levers and during movement into its other eXtreme posi-4V tion to trip said latch out of engagement with the other of said levers, a spring operatively Vcon- V- nected to said levers at points below the pivots thereof, and means operatively connectingV saidV spring to lsaid operating member to provide for l snap movement of said contact element Vbetween its, extreme circuit'l controlling l positions upon tripping of said latch. n y 4. The combination with a Ystationary frame, a reciprocable contactcarrier and asnapoperating mechanism Vtherefor carried by said' frame, saidV contact carrierbeing located above said frame and having bridging contacts yieldingly mounted thereon,V an insulating Ybase superimposed upon said frame and having its under side' recessed to receive'r said lcontact Ycarrier and its associated contacts, and a plurality of stationary Vcontacts mounted upon said base to be `engaged 5.V The combination with a stationary framaaaYYY reciprocable contact element and a snap YAYoper-7v Vating mechanism therefor carriedbyY said frame,A y said contact element including a horizontallyfdis- Y posed elongated insulating support havingra pair of horizontally disposed bridging contacts mount-. ed thereon, an insulating base superimposed upon saidframe and having its under side recessed to j receive said contact carrier and `its associated bridging contactsg and a 4plurality of Y'stationary contacts mounted upon said base to be engaged by said bridging contacts, said stationary contacts extending upwardly through openings in said base and each having a right angle terminal portion upon the upper end thereof for securement to the upper face of said base and securing means associated with the terminal portions of said contacts permitting adjustment of said contacts with respect to their associated bridging contacts.

6. In a control device, in combination, an enclosing casing, a control switch mounted within said casing and an operating head for said switch detachably mounted upon the exterior of said casing and having an axially movable push rod associated therewith extending through an opening in said casing and connected to said control switch to operate the same, said operating head being attachable to said casing in various angular positions with respect thereto.

7. The combination with a control switch and an enclosing casing therefor, of a reciprocable push rod operatively connected to said switch and extending outwardly through an opening in said casing, and an operating head for said push rod detachably mounted upon the exterior of said casing, said operating head including a supporting member attachable to said wall in any one of a plurality of angular positions, and a cam operating shaft rotatably mounted within an opening in said member and disposed at right angles to said push rod for engagement with the outer end thereof.

8. The combination with a control switch and an enclosing casing therefor, of a reciprocable push rod operatively connected to said switch and extending outwardly through an opening in said casing, an operating head associated with said push rod detachably mounted upon the exterior of said casing, said operating head including a supporting member attachable to said casing in any one of a, plurality of angular positions, a cam operating shaft rotatably mounted upon said supporting member and disposed at right angles to said push rod for engagement with the outer end thereof, and an operating lever located to one side of said supporting member and adjustab-ly secured to said operating shaft to permit variation of the angular position thereof with respect to said shaft.

9. The combination with a control switch hav- 10 ing a reciprocable operating element, an enclosing casing therefor, a reciprocable push rod extending through an opening in said casing and having its inner end detachably secured to said switch 'operating element, a biasing spring associated with the outer end of said push rod for normally maintaining said switch in a given position and an operating head for said push rod detachably mounted upon the exterior of said casing, said operating head including a rotatable cam shaft disposed at right angles to said push rod for engagement with the outer end thereof, and a supporting member for said cam shaft attachable to said casing in any one of a plurality of equally spaced angular positions.

10. In combination, a control switch, an enclosing casing therefor, a reciprocable push rod operatively connected to said switch and extend` ing outwardly through an opening in said casing, and an operating head for said push rod attachable to said casing in any one of a plurality of equally spaced angular positions, said operating head including a cam operating shaft disposed at right angles to said push rod for engagement with the outer end thereof, an operating lever having a bored hub portion for receiving said shaft, said hub portion having a plurality of equally spaced notches formed on the interior thereof and said shaft having a dierent number of equally spaced notches formed on the periphery thereof, and means for holding said lever in assembled position upon said shaft, said means including a pin insertable into the space formed by selected registering notches in said hub portion and said operating element to lock said operating lever in selected angular positions upon said shaft.

ALLAN CHARBONNEAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 665,514 Ely Jan. 8, 1901 2,205,380 Batcheller June 25, 1940 970,264 Peterson Sept. 13, 1910 2,294,559 Jeffrey Sept. 1, 1942 

